Found on Canning Craze
2/3 cup chopped seeded orange (peeled)
4 cups pitted sweet cherries
4 Tbsp lemon juice
3.5 cups granulated sugar
Here’s how we made it: In a large pot combine the cherries, orange and lemon juice. Bring the mixture to a boil over medium high, then reduce the heat, cover and maintain a boil, stirring often. Boil for 20 minutes or so until the peels are softening and the cherries are breaking down a bit. After 20 minutes add the sugar, maintaining a boil. Continue to boil hard, stirring frequently for about 30 minutes, until gel stage is reached.
Bring to a full rolling boil and process for 15 minutes.